[Gary_W]

Hi Bob,

I'm only 3 weeks in with pumping so my advice may not be as valid as some of the old timers here on the pump. Also, I'm using an Animas not a Medtronic. They all work out insulin on board in a slightly different way. The Animas lays out for you how it does the maths; not sure the Medtronic does?

IMO, you need to figure out HOW it is doing the maths and until you fully understand how it does it, you need to be careful of the advice that 'insulin on board' gives you. Doing 7 bolus' in a day is fine, but the Animas can occasionally tell you that you don't need to bolus due to IoB. If you are confident that you got the carb counting right from the last thing you ate then in theory all the IoB you have is already 'spoken for' with the meal or snack you last ate. If you eat more, you still need to cover it.

As an example, imagine a carb ratio of 1:10 and you eat 100g of carbs for a main meal. 10u of insulin goes in. A couple of hours later, you decide to eat a 40g carbs desert. Your pump tells you that you still have 4u of insulin on board. Does that mean you can eat the desert scot free and not bolus? In my opinion, no it doesn't.

I'll get down from my soap-box now. It's just a little personal niggle of mine as I think that IoB is poorly explained in the Aninmas manual and until I discussed it on here and had a serious amount of circular brainstorming I just didn't get it. I will bet that it gets a lot of people into trouble and has the capacity to cause seemingly inexplicable highs (why am I high after eating that desert? I had 4u of insulin still active...).

Gary